A number of hull marine indicia markings, such as Plimsoll lines, draft markings, ship's name and port designation are required by law. Additional hull markings are often desired. For instance, it is advantageous to visibly convey such information as the location of various discharge valves, fuel lines, tank locations, corners of tanks, bulkhead frames, sea chests, and hull sections to be marked to facilitate underwater inspections and surveys.
Typically, a raised weld bead is used to create the marking, whereupon the marking is painted using the weld bead as a guide. However, providing these weld beads is a labor intensive process, particularly when the marking is located on the exterior side of a fuel oil, lube oil, oily sludge, natural gas chemicals or similar products. Conformance with shipbuilding specifications requires that a special hot work permit be obtained prior to welding opposite a tank. To obtain a hot work permit, the tank may have to be emptied completely, cleaned, or have the level of its contents changed, and determined to be purged of oxygen prior to beginning the welding process. Thus, this method is undesirable for many reasons.
Another prior art method for marking a hull involves center punches and painting over the punches. These center punches, however, are easily lost whenever the hull is blasted before painting.